Drink your coffee faster. Honestly the whole product is a solution looking for a problem.
I cracked open one of my Ember mugs after it died. The small pcb that is at the base of the mug has a sensing trace going up into the wall of the mug. Its capacitive, you can see the pad on the component. Nothing fancy.
so theoretically if someone made a replacement pcb with an array sensor it could be modded to read the level of liquid?